Whether you see them as "broad-shouldered” targets for punitive taxes, or whether you champagne-toast them as valued high net worth entrepreneurs, one thing is inarguable: Scotland needs many more rich people living and working here to become a prosperous, productive economy, that nurtures the life chances of its most vulnerable and disadvantaged citizens.

At present there are only around 14,000 Scots who pay the additional rate of income tax (on annual earnings of over £150,000) although even this 1% of the population contributes a staggering 26% of the income tax take. Only those ideologically welded to the idea that the poor are poor because the rich are rich would argue that a successful Scotland, under any constitutional arrangement, needs fewer of these high-earners, not more.

Most of all it needs more “angels”, wealthy and super-wealthy individuals prepared to rain down their hard-earned (and unearned) cash into the country's burgeoning start-up economy, its young ventures and the nascent billion pound companies. Only a critical mass of these will make Scotland feel more like Singapore or Massachusetts.

The good news is that there is a solid base to build on. A recent study by lawyers Harper Macleod found that angel investors are disproportionately prominent in Scotland given the higher concentrations of wealth elsewhere in the world. In 2013 they provided over £27 million of investment in Scottish start-ups, dispensing cash in packages in the region of £20,000-£750,000. Research by the export and investment agency Scottish Development International (SDI) claims that Scotland has "more business angel investment per head of population than any other country in Europe".

LINC Scotland, the national association for business angels in Scotland, currently has 19 angel syndicate members comprising more than 800 individual investors.

The question, never posed so crudely in Scottish political discourse, is how to nurture more of the enlightened rich, how to keep them here and how to encourage more of them to invest in the start-up economy?

According to James Sproule, chief economist and head of strategy for the Institute of Directors, a first move for government is to be more creative in how it seeks to move private wealth around the economy. On a visit to Scotland last week where he was promoting a new IoD paper called “Opening the equity economy” Sproule told the Sunday Herald, that tax is not the most constructive way of siphoning the resources of the rich into the financial ecosystem, and he criticised the prevailing views of wealth within much of the Scottish political discourse:

“I get the impression that the much of the narrative amounts to saying ‘We’re going to stop you spending money on champagne and feed poor people instead’. That's extraordinarily naïve.”

“One of the things we are calling for is for, and this is applicable to the Scottish Government and to the Westminster Government. Be very careful about trying to raise more taxes now, because you are looking at constantly trying to raising taxes from a very small percentage of people who are very highly taxed already and economically these people have a disproportionate propensity to save.”

“You are going to be raiding the people who are likely to be doing the investing in long term. Given that we are in the middle of a tech revolution, denying ourselves the ability to invest is probably a particularly short-sighted approach.”

Sproule and the IoD’s Scotland director David Watt are projecting an upbeat message about the level of entrepreneurial activity in a healthily growing economy in Scotland and the UK, which, they claim, could acquire more momentum if there was wider participation in financing the “entrepreneurial and digital revolution” in which Britain is an undisputed world leader. The evidence cited is encouraging, both at UK level from their own study, and in Scotland from Strathclyde University Business School’s Global Entrepreneurship Monitor (GEM).

The former cites a record 586,000 UK business start-ups in 2014/5, up 10% from the previous year and up 23% since 2011/12. In the last four years the UK has moved from 14th place to 4th in the European section of the Global Entrepreneurship Index, although it notes that the UK still lags in skills, access to finance and product development. With the internet being the fastest and cheapest route to big markets, the UK is way out ahead according to Boston Consulting Group, with the internet economy a massive 12.4% of GDP (in South Korea, the runner up is only 8% and the EU average is 5.7%).

Although Scotland’s ecommerce and internet economy has been under-supported by the Scottish Government and Scottish Enterprise, the most recent edition of the GEM survey found total early-stage entrepreneurial activity “very close to the UK rate” and “average for participating innovation-driven nations”.

According to the IoD report, which praises in passing the controversial appointment of Scots lingerie boss Michelle Mone to lead an enquiry into boosting entrepreneurialism in disadvantaged communities:

“Although new businesses in Britain have a more open attitude towards financing expansion through equity rather than debt, we still lag the US when it comes to our equity infrastructure. The UK’s biggest weakness, on various measures of entrepreneurialism is on our attitude to risk capital.”

The solution, according to the IoD, already exists in the shape of “underutilised government initiatives”, currently mainly known to accountants and IFAs, the Enterprise Investment Scheme (EIS) a tax-friendly way of purchasing shares in high risk companies, and its younger sibling the Seed Enterprise Investment Scheme (SEIS), aimed specifically at early-stage schemes.

Using these could “unlock a wave of new investors, build up equity finance in the UK and cement its position as one of the best places in the world to start, set-up, run and invest in a business.”

The IoD is proposing a range of specific ways in which the UK Government could put boosters under these schemes, including bundling EIS and SEIS investments in a new super-ISA wrapper, including peer-to-peer loans and crowdfunding investments, street-level advertising of the schemes, scrapping rules restricting how “knowledge intensive” companies are defined, and extending the SEIS qualifying limits from two year-old to four year-old companies.

All of which, according to James Sproule, will help transform the business growth environment in the UK, putting excess wealth to work more creatively than the current tax system does and mitigating the sense, implicit in the increasingly left-wing discourse of the main political parties in Scotland (let alone a Corbynite UK opposition) that the primary job of the rich is to stick around to be squeezed:

“If the rich feel that the landscape has become unfriendly and look for other places to invest their money, and that’s the last thing you want.” Sproule says “We are talking about a great deal more than champagne money here. You don’t want people to move it from the invested economy to current consumption, and that’s what Edinburgh and Westminster seem intent on doing. I think it’s a mistake.”

An obvious first step would be making business and tax conditions for the well-heeled and entrepreneurially ambitious in Scotland as friendly as, or more friendly than, the rest of the UK. This is a goal that is implied, very vaguely, by the Scottish Government whose Economic Strategy of March 2015 refers repeatedly to “supporting entrepreneurialism” without saying how exactly.

But, especially since the culling of the corporate tax cut promise from Scottish Government prospectus by a more left-leaning First Minister Nicola Sturgeon, political body language in Scotland has not being reassuring to the financial and entrepreneurial elite.

One of those raising questions is Angus MacDonald, a serial entrepreneur and business angel, whose interests include financial publishing, renewable energy and internet education, also founder of the corporate endurance race the Caledonian Challenge which has raised £13m for Foundation Scotland since 1996.

In an open letter to his MSP John Swinney last month, MacDonald accused the current Scottish Government of only “claiming to be business-friendly” while pursuing tax and land ownership policies that will result in “a considerably reduced tax take, the results of which will ultimately be borne by those most in need of public services.”

He wrote: “Good employers do not resent paying even substantial amounts in tax, as long as these are fairly applied. However if that business owner sees Land and Buildings Transaction Tax (LBTT) on top-end houses set at a rate more than twice that of England, he or she may think again.”

“If he or she reads about new bands of council taxes being considered on higher value property and a local income tax based on ability to pay, and the possibility of a higher Scottish Rate of Income Tax then you can guarantee that these people will be wondering whether to relocate their business down south.”

Swinney responded by asserting Scotland’s healthy growth statistics, continuing high levels of investment and “determination to create a dynamic economic environment for business to develop in our country… the Scottish Government attaches the greatest importance to boosting the economy, creating a sound business environment and attracting investment to create opportunities for our citizens.”

MacDonald how remains unconvinced. “Mr Swinney is a sensible and sincere politician but I fear he is being told [by his civil servants] what he wants to hear. He doesn’t address the fact the prohibitive level of the LBBT in Scotland is causing the disappearance of top end value transactions that will negate the financial balance he is hoping to achieve.

“I can assure him that people with significant businesses are avoiding investing in Scotland right now and the property market in Scotland is awash with high end properties with no buyers. Confidence amongst larger tax payers is low.”

Would dinner party chat about perceived hostility to wealth put the breaks on his angel activities within the Scottish economy? Not necessarily he concedes “but if there were two companies that I liked equally on both sides of the border, then I would not chose the Scottish one, because I think the tax regime was more likely to change negatively against the Scottish one.”

Attracting wealthier people to come and live and spread their angel wings within the Scottish economy is a sine qua non of national prosperity, but it is also a goal that is unlikely ever to be made explicit in the current political climate. One problem is that the means to do it are politically unspeakable, unless spoken by ideologically-untrammelled academics.

The Glasgow University professor John McLaren, for example argues that:

“One of the ways you could increase the tax take in Scotland after the Scotland Bill powers are put through is actually by lowering the higher rate of income tax. There are fewer higher rate payers in Scotland so the money you would lose by lowering that rate is not as great as it is in the UK as a whole.”

“The impact would be relatively low and then you have the attraction and possibility of attracting in a lot more richer people from the rest of the UK, so net, the overall tax take will be higher. Actually income tax is one of the best tax rates to achieve that goal in that it the tax that Scotland has control of.”

The sheer improbability of tax cuts for the rich ever being announced by the Scottish Government illustrates the fact that politics is about a lot more than achieving straightforward economic benefits. Nevertheless, success for this administration, and any of its successors Scotland will depend on their political skill in making more wealthy, investment-minded angels feel enthusiastic about coming to live here, and making the rest of us feel ok with that.